Typically, a valve includes a fluid inlet passage coupled through an orifice to a fluid outlet passage and a fluid flow control or closure member operative relative to the orifice to control the amount of fluid flow through the valve. The closure member may include a valve plug having a surface that may engage a valve seat surrounding the orifice to prevent the flow of fluid through the valve.
A process control plant can contain hundreds to thousands of valves throughout the plant, many of which may be manually operated valves. Such manually operated valves are used for many different purposes including, for example, isolating equipment, draining vessels, flushing piping, bypassing equipment, etc. During operation of the plant, these valves must be in the proper position (i.e., either open or closed) for the plant to operate effectively and safely.
Before the start up of a plant or a portion of the plant (e.g., a single loop) the position of each manually operated valve must be validated. Typically, this requires sending a person into the plant with a list of valves that are to be verified and visually inspecting the positions of the valves. This is very time consuming, risks human error and exposes the person to potential safety hazards.